Identification-robust moment-based tests for Markov switching in autoregressive models

ABSTRACT

This paper develops tests of the null hypothesis of linearity in the context of autoregressive models with Markov-switching means and variances. These tests are robust to the identification failures that plague conventional likelihood-based inference methods. The approach exploits the moments of normal mixtures implied by the regime-switching process and uses Monte Carlo test techniques to deal with the presence of an autoregressive component in the model specification. The proposed tests have very respectable power in comparison with the optimal tests for Markov-switching parameters of Carrasco et al. (2014 Carrasco, M., Hu, L., Ploberger, W. (2014). Optimal test for Markov switching parameters. Econometrica 82(2):765–784.[Crossref], [Web of Science ®] , [Google Scholar]), and they are also quite attractive owing to their computational simplicity. The new tests are illustrated with an empirical application to an autoregressive model of USA output growth.     

Improving outcomes for children in out‐of‐home care: the role of therapeutic foster care

How best to support children and young people in foster care remains a challenge for child welfare. There has been little Australian research on the outcomes for children and young people placed in therapeutic foster care (TFC). This article aims to address this knowledge gap, presenting the evaluation of a state‐wide model of TFC known as the Circle Program operating in Victoria, Australia. Data sources for the study were case assessment analysis; surveys of foster carers, program workers and other stakeholders in the sector; and both focus groups and individual interviews with foster care workers. The evaluation found that the Circle Program lessened the number of unplanned exits of children from foster placements compared with generalist foster care. Another important finding was that the Circle Program positively influenced foster carers' decisions to stay in the carer role. Key components perceived as contributing to outcomes of the Circle Program included enhanced training of foster carers, intensive carer support, specialist therapeutic support to the child and carer, therapeutic service to family members and a network of services to provide support to the child.     

Alcohol use and strenuous physical activity in college students: A longitudinal test of 2 explanatory models of health behavior

Objective: To help clarify the effect of gender on the bidirectional relationship between alcohol use and strenuous physical activity in college students. Participants: Five hundred twenty-four (52% female) college students recruited in August 2008 and 2009 and followed up in April 2009 and April 2011, respectively. Methods: Participants reported their alcohol use and strenuous physical activity on 2 occasions (baseline and follow-up) spaced approximately 1 or 2 years apart. Results: For females, alcohol use quantity at baseline was associated with increased strenuous physical activity at 1- and 2-year follow-ups, and alcohol use frequency at baseline was associated with decreased strenuous physical activity at 2-year follow-up. For males, alcohol use frequency at baseline predicted decreased strenuous physical activity at 1-year follow-up. Conclusions: Gender differences may be explained from an eating disorders perspective such that women use physical activity as a compensatory strategy to combat potential weight gain from calories consumed during alcohol use.     

Exploring how the social model of disability can be re-invigorated for autism: in response to Jonathan Levitt

Levitt argues that the social model of disability needs to be re-invigorated, potentially by adapting the tool for separate countries. The social model has been successfully applied for some disabled groups in the United Kingdom. However, the social model is not implemented for neurodivergent labels such as autism, through the negative language of autism, causing severe problems for autistic individuals’ daily lives. The social model can be re-invigorated for autism, removing social barriers by changing non-autistic people’s attitudes towards autism through ensuring positive language of autism, preventing the categorisation of autism and fully enacting The Autism Act 2009 and The Equality Act 2010.     

Elevated phosphorus: dynamics during four years of green roof development

Green roofs are emerging engineered ecosystems that provide multiple benefits, but many are constructed with nutrient-rich substrate and have been found to leach out high levels of phosphorus (P) in runoff. It is unclear, however, how long green roofs act as sources of P or what mechanisms are responsible for these net losses. We measured P concentrations in runoff water over 4 years from a 1–5 year old extensive green roof in Cincinnati, OH, USA, produced a model to predict runoff P levels into the future, and validated predictions using runoff from 2 nearby extensive green roofs. P concentrations in runoff from the focal green roof were on par with heavily fertilized agroecosystems and displayed strong seasonal dynamics and a rapid decline over the 4-year study. Runoff measurements and changes in substrate P content over a 2-year period were used to estimate a mass balance for green roof P. P loss from the substrate was substantial (4.55 ± 2.3 g P/m²/yr), but only a small portion of the loss was attributable to leaching of P in runoff (0.19–0.65 g P/m²/yr). Missing P may be attributed to a combination of plant uptake and altered P form and binding strength, but further research is needed to precisely identify the mechanisms of P depletion. Our results also suggest that these and similar extensive green roofs are likely to act as environmentally significant sources of P for 10 or more years following roof installation, highlighting the need for reductions in initial substrate P content.     

How Visual is Visual Prediction?

Infants are readily able to use their recent experience to shape their future behavior. Recent work has confirmed that infants generate neural predictions based on their recent experience (Emberson, Richards, & Aslin, 2015) and that neural predictions trigger visual system activity similar to that elicited by visual stimulation. This study uses behavioral methods to ask, how visual is visual prediction? In Experiment 1, we confirmed that when additional trials provide additional visual experience with the experimental shape, infants exhibit a robust novelty preference. In Experiment 2, we removed the visual stimulus from some trials and presented the predictive auditory cue alone, allowing the effects of neural prediction to be assessed. We found no evidence of looking preferences at test, suggesting that visual prediction does not contribute to the computation of visual familiarity. In Experiment 3, we provided infants with a degraded visual stimulus to test whether visual prediction could bias visual perception under ambiguous conditions. Again, we found no evidence of looking preferences at test, suggesting that visual prediction is not biasing perception of an uncertain stimulus. Overall, our results suggest that visual prediction is not visual, in the strictest sense, despite the presence of visual system activation.     

Workplace aggression against health care workers,law enforcement officials,and bus drivers: Differences in prevalence,perceptions, and psychological consequences

Investigations into workplace aggression (WPA) remain largely occupation specific, with few studies using a comparative approach. The aim of the present study was to compare the health care, law enforcement, and public transportation sectors with regards to the prevalence of different types of WPA, the perceptions of workers toward WPA, and the psychological consequences of such acts. A cross-sectional survey was completed by 1,774 workers in Canada. Multinomial regressions were utilized to address the objectives. Findings revealed that verbal abuse victimization was particularly common in bus drivers, witnessing death threats was most frequent among law enforcement officials, and witnessing all types of WPA was most common among health care workers. Although bus drivers did not normalize WPA, they feared complaining about violence to their employer and thought it useless to talk it about unless wounds were visible. Fear of complaining about violence to colleagues was prevalent in health care and law enforcement, both sectors in which WPA was normalized. Finally, flashbacks and irritability following WPA were most likely to affect bus drivers whereas health care workers experienced hypervigilance to a greater extent. Strategies to tailor primary, secondary, and tertiary prevention according to these distinctions are suggested to offer a better-informed response to WPA.     

“Friendly” Initiatives: An Emerging Approach to Improve Communities for Vulnerable Populations

A growing number of cities and towns are implementing “friendly” initiatives to change the community’s social and physical infrastructure to address the needs of a particular vulnerable segment of their population. Three prominent examples are aging-friendly, child-friendly, and immigrant-friendly initiatives. Although the limited but growing literature describes these initiatives as promising strategies to improve the quality of life of the targeted population, to date there has been little written about the underlying goals, values, and assumptions of these efforts. Using the value-critical approach, this article aims to better understand these aspects of population-friendly initiatives by examining the scholarly and grey literature. Social workers engaged in community and policy practice can play a key role in these efforts and call attention to the ways they may alleviate or exacerbate inequities. Future research is needed to assess the effects of these initiatives on their targeted population as well as other community residents.